Energy and protein demands for optimal egg production including maintenance requirements of female tilapiaOreochromis niloticus

Abstract

The daily requirements of a spawning tilapia female are quantified from the sum of the requirements for maintenance plus production of eggs. The protein and energy requirements for maintenance and the cost of depositing energy and protein towards growth or gonadal products were determined by supplying feed at increasing levels from zero to the maximum intake. Comparative body composition analyses of the females in addition to the amount and the content of eggs enabled us to quantify the total energy and protein channelled into weight gain or alternatively into egg production. The amount of eggs produced increased with increasing feeding levels and ranged between 0.7 and 1.1 g eggs per kg−1 fish day−1. Regardless of feed allowance, the composition of eggs was similar and contained 235 mg protein and 10.5 kJ g−1 wet weight. In contrast, the whole body of tilapia contained 167 mg protein and 6.7 kJ g−1 on average. The energy requirement for maintenance was calculated to be 59.46 kJ × BW (kg)0.80 and 0.98 g × BW (kg)0.70 for digestible protein. The partial efficiency of producing gonads was 0.67 and 0.59 for digestible energy and digestible protein respectively.